Know all Types of Sensors with their Circuits Diagrams

Generally, we use conventional wall socket switchboards for switching on the industrial appliances or home appliances such as fan, cooler, industrial motors, and so on. But, it is very difficult to operate the switches regularly. Hence, home automation and industrial automation systems are developed for ease of controlling all the required electrical and electronics loads. This automation in power system can be designed using various types of sensors and sensor circuits.

What is Sensor?

A device which gives an output by detecting the changes in quantities or events can be defined as a sensor. Generally, sensors produce an electrical signal or optical output signal corresponding to the changes in the inputs. There are different types of sensors, for example, consider a thermocouple which can be considered as temperature sensor that produces an output voltage based on the input temperature changes.

Different Types of Sensors in Electronics

In our day-to-day life we got used to use different types of sensors frequently in our power systems such as electrical and electronics appliances, load control systems, home automation or industrial automation, and so on.

Different Types of Sensors

All types of sensors can be basically classified into analog sensors and digital sensors. But, there are a few types of sensors such as temperature sensors, IR sensors, ultrasonic sensors, pressure sensors, proximity sensors, and touch sensors are frequently used in most of the electronics applications.

Temperature Sensor

IR Sensor

Ultrasonic Sensor

Touch Sensor

Proximity Sensors

Pressure Sensor

Level Sensors

Smoke and Gas Sensors

Sensors with Circuit Daigrams:

Here, in this article we want to make you know all types of sensors with circuits.

Temperature Sensor

Temperature Sensor (Thermistor)

Temperature is one of the most commonly measured environmental quantity for different reasons. There are different types of temperature sensors that can measure temperature, such as thermocouple, thermistors, semiconductor temperature sensors, resistance temperature detectors (RTDs), and so on. Based on the requirement, different types of sensors are used for measuring temperature in different applications.

Temperature Sensor Circuit

A simple temperature sensor with circuit can be used for switching on or off the load at specific temperature which is detected by the temperature sensor (thermistor is used here). The circuit consists of battery, thermistor, transistors, and relay which are connected as shown in the figure.

Temperature Sensor (Thermistor) with Circuit

The relay is activated by the temperature sensor by detecting the desired temperature. Thus, the relay switches on the load connected to it (the load can be AC or DC). We can use this circuit for controlling the fan automatically based on temperature.

Practical Application of Temperature Sensor

Primarily, consider temperature sensors which are again classified into different types of sensors such as thermistors, digital temperature sensors, and so on.

Programmable Digital Temperature Controller Circuit by Edgefxkits.com

Programmable digital temperature controller is a practical embedded systems based electronic project designed by www.edgefxkits.com that is used for controlling the temperature of any device based on the requirement of industrial applications. The digital temperature sensor circuit kit is shown in the figure below.

The project circuit block diagram can be represented as follows with different blocks as shown in the figure.

The power supply block consists of AC 230V supply, step down transformer for stepping down the voltage, rectifier for rectification of voltage from AC to DC, voltage regulator for maintaining constant output DC voltage for giving input to the project circuit.

The LCD display is interfaced to the 8051 microcontroller for displaying the temperature readings in the range of -55degrees C to +125degrees C. The digital temperature sensor IC DS1621 is used for providing 9-bit temperature readings to the microcontroller. The EEPROM non-volatile memory is used to store user defined (maximum and minimum) temperature settings through a set of switches to the 8051 microcontroller. A relay is connected to the microcontroller which can be driven using the transistor driver. The load can be driven using this relay (here load is represented as lamp for demonstration purpose).

IR Sensor

IR Sensor

The small phototchips having a photocell which are used to emit and detect the infrared light are called as IR sensors. IR sensors are generally used for designing remote control technology. IR sensors can be used for detecting obstacles of robotic vehicle and thus control the direction of the robotic vehicle. There are different types of sensors which can be used for detecting infrared lights.

IR Sensor Circuit

A simple IR sensor circuit is used in our day-to-day life as remote control for TV. It consists of IR emitter circuit and IR receiver circuits which can be designed as shown in the figure.

The IR emitter circuit which is used as remote by the controller is used for emitting infrared light. This infrared light is sent or transmitted towards the IR receiver circuit which interfaces to the device like TV or IR remote controlled robot. Based on the commands received the TV or robot is controlled.

Practical Application of IR Sensor

IR sensors are frequently used to design TV remotes. It is a simple IR sensor based electronics project used for controlling a robotic vehicle remotely using the general TV remote or IR remote. The IR sensor controlled robotic vehicle project circuit is shown in the figure.

The block diagram of IR controlled robotic vehicle consists of different blocks such as motors and motor diver interfaced to the 8051 microcontroller, battery for power supply, IR receiver block, and TV remote or IR remote as shown in the figure.

Here, the IR sensor based TV remote is used for sending commands to the robotic vehicle remotely by the user. Based on the commands received by the IR receiver interfaced to the microcontroller at the receiver end. The microcontroller generates appropriate signals to drive the motors such that to control the direction of robotic vehicle in forward or backward or left or right.

Ultrasonic Sensor

A transducer that works on the principle similar to the sonar or radar and estimate attributes of the target by interpreting is called as ultrasonic sensors or transceivers. There are different types of sensors that are classified as active and passive ultrasonic sensors that can be differentiated based on the working of sensors.

Ultrasonic Sensor

The high frequency sound waves generated by active ultrasonic sensors are received back by the ultrasonic sensor for evaluating the echo. Thus, the time interval taken for transmitting and receiving the echo is used for determining the distance to an object. But, passive ultrasonic sensors are just used for detecting ultrasonic noise which is present under specific conditions.

Ultrasonic Sensor Circuit

The ultrasonic module shown in the above figure consists of ultrasonic transmitter, receiver, and control circuit. The practical application of ultrasonic sensor with circuit can be used as ultrasonic distance sensor circuit as shown below.

Ultrasonic Sensor with Circuit

Whenever power supply is given to the circuit, then ultrasonic waves are generated and transmitted from the sensor and reflected back from an obstacle or an object ahead of it. Then, the receiver receives it and the total time taken for sending and receiving is used for calculating the distance between the object and sensor. The microcontroller is used for processing and controlling entire operations using programming techniques. The LCD display is interfaced to the circuit for displaying the distance (generally in cm).

Practical Application of Ultrasonic Sensor

Ultrasonic sensor with circuit can be used for measuring distance of an object. This method is used, where we cannot implement the conventional methods to measure like inaccessible areas such as high temperature or pressure zones, etc. The ultrasonic sensor based distance measurement project circuit kit is shown in the figure.

The distance measurement by ultrasonic sensor project circuit block diagram is shown in the block diagram below. It consists of different blocks such as a power supply block, LCD display, ultrasonic module, an object whose distance has to be measured, and the 8051 microcontroller.

The ultrasonic transducer used in this project consists of an ultrasonic transmitter and receiver. The waves transmitted from ultrasonic transmitter are reflected back to the ultrasonic receiver from the object. The time taken for sending and receiving back these waves is calculated by using the velocity of sound.

Touch Sensor

Touch Sensor

Touch sensors can be defined as switches that are activated by the touch. There are different types of touch sensors that are classified based on type of touch such as capacitance touch switch, resistance touch switch, and piezo touch switch.

Touch Sensor Circuit

The circuit represents a simple application of touch sensor which consists of a 555 timer operating in monostable mode, touch sensor or plate, LED, battery, and basic electronic components.

Touch Sensor with Circuit

The circuit is connected as shown in the above figure. During normal state, when the touch plate is not touched, then the LED remains in off state. If once the touch plate is touched, then a signal is given to the 555 timer. By sensing the signal received form touch plate, the 555 timer activates the LED and thus the LED glows indicating the touch made to the touch sensor or plate.

Practical Application of Touch Sensor

A touch sensitive load is designed for controlling the load. The touch controlled load switch project circuit kit is shown in the figure.

Touch Controlled Load Switch Circuit Project Kit by Edgefxkits.com

Touch sensor principle based touch controlled load switch consists of different blocks such as power supply block, 555 timer, touch sensor plate or touch plate, relay, and load as shown in the block diagram of touch controlled load switch.

Touch Controlled Load Switch Circuit Block Diagram by Edgefxkits.com

The 555 timer used in the circuit is connected in monostable mode, which is used to drive a relay for switching ON a load for a fixed time duration. The trigger pin of the 555 timer is connected to the touch plate, thus, 555 timer can be triggered by touch. Whenever 555 timer is triggered by touch (voltage develops with human body touch) it delivers logic high for a fixed time interval. This fixed time can interval can be changed by changing the RC time constant connected to the timer. Thus, the output of the 555 timer drives the load through the relay and the load turns off automatically after fixed time duration.

Similarly, we can develop simple and innovative electrical and electronics projects using more advanced sensors such as a PIR sensor based automatic door opening system. Pressure sensor based electricity generation which can be implemented by placing the piezoelectric plates (these are one type of pressure sensors) under a speed breaker on highways for generating electricity for highway street lights. Proximity sensor based proximity detector circuit.

For designing different types of sensor based circuits you can download our free eBook to design electronics projects on your own. You can also approach us for technical help by posting your ideas in the comments section below.Here is a question for you, what are impact sensors?

Hi Harsha
Yes, there is a sensor for directions and it is called as direction sensor.
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Hi Anandam
Thanks for your compliment
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Hi Saina,
Thanks for your compliment
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Hi Prasad
Thanks for your compliment. ECG sensor is to study the electrical activities of the heart.
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Thank you very much for telling me how much you have enjoyed reading my column
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Hi john Nap, knust, Ghana
I sincerely appreciate your kind response regarding my article.
We’re often asked when to use smoke sensors and when to use gas sensors. Both types of sensors can detect a fire, but these products are actually designed to serve different needs. for example, take the Gas Sensor, used to gas leakage detection to prevent the fire accident.
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Hi Jacob
Thank you so much for your feedback
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Hi Sarah
I sincerely appreciate your kind response regarding my article
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Hi Magaji Hud
I sincerely appreciate your kind response regarding my article. As per your query, A gas sensor is used to detect the toxic gas leakage.
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Hi BHANUCHANDER
As per your requirement, pH sensor can be used.please visit our domestic website https://www.elprocus.com
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Hi Christy
By using MQ2, and MQ6 sensor you can detect the gas
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Hi Tarun,
i am looking to see what technology is best suited for my application. I need to create boundary (line) and if any part of a machine brakes the line entering the no go zone it could sound a alarm. The electronic transmitter unit and the alarm should be battery operated. The rang I am looking is about 30m. Please advise what is the best technology that I could use ie; IR or ultrasound or similar.

Hi Rajesh Manki
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Hi pramod singh munda
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